<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>变量特点</title>
    <script>
        function fn(){
            let i = 1;
            console.log(typeof i);
            i = "admin";
            console.log(typeof(i));
            i = true;
            console.log(typeof i);
        }
    </script>
</head>
<body>
<button onclick="fn()">变量特点</button>
</body>
</html>